Promise

controllers.application.js

import Ember from 'ember';

Ember.onerror = function (error) {
  console.log('Error: ' + error);
}

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  initDeferred: Ember.on('init', function() {
		var deferred = Ember.RSVP.defer();
		var deferred2 = Ember.RSVP.defer();
    
    deferred.promise.then(function() {
      console.log('Resolved');
    }).catch(function() {
      console.log('Catched');
    });

    deferred.promise.finally(function() {
      console.log('Finally');
    });
    
    deferred2.promise.then(function() {
      console.log('Resolved2');
    }).catch(function() {
      console.log('Catched2');
    }).finally(function() {
      console.log('Finally2');
    });
    
    this.set('deferred', deferred);
    this.set('deferred2', deferred2);
	}),
  
  actions: {
  	foo: function() {
    	this.get('deferred').reject('reject');
    	this.get('deferred2').reject('reject2');
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
<button {{action 'foo'}}>Hello</button>
<br>
<br>

twiddle.json

{
  "version": "0.13.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.16.2",
    "ember-template-compiler": "2.16.2",
    "ember-testing": "2.16.2"
  },
  "addons": {
    "ember-data": "2.16.3"
  }
}